Demand within the industry has recently extended to the manufacture of multicomponent cigarettes, each of which comprises a number of end-to-end portions, at least one of which is normally defined by a filter element, and at least another of which is defined by an aromatic, preferably tobacco-based, element.
Manufacturing cigarettes of this type calls for an assembly machine adaptable to different portion combinations.
Patent Application US-A1-2006201523, for example, describes a filter-tipped cigarette manufacturing machine, in which the cigarette comprises a tobacco portion, and a combination filter in turn comprising at least three different component parts. The cigarette manufacturing machine comprises a combining unit for forming groups of filter portions, each group comprising three different filter portions aligned axially and contacting end to end; and a unit for forming a continuous tobacco rod, which is cut into double-length portions and fed to a wrapping unit. The wrapping unit receives a succession of groups of double-length filter portions from the combining unit and a succession of double-length tobacco portions, and is designed to form groups, each comprising a tobacco portion, a double-length filter portion, and a tobacco portion, and to wrap them in a sheet of wrapping material to form double-length cigarettes, which are then cut into individual cigarettes. The manufacturing machine is T- or L-shaped, in which the unit for forming the tobacco portions is perpendicular to the assembly comprising the combining unit and the wrapping unit.
The manufacturing machine described in US-A1-2006201523 has several drawbacks, by being bulky and not allowing for fast, easy brand change (i.e. switching from production of one type of cigarette to another). To meet changing market demand, on the other hand, a modern manufacturing machine of this type must be capable of producing different types of cigarettes effectively and efficiently.
Documents US-A1-2006157070 and WO-A1-2006070289 describe cigarette manufacturing assembly machines comprising a combining unit for forming groups of filter elements, each comprising at least two different first filter elements aligned axially, and in which the groups of filter elements are fed perpendicularly to their central axis. The combining unit comprises a number of structurally similar, though not identical, feed stations, each of which supplies a respective filter element to form the groups of filter elements; and each feed station comprises an insertion drum, which receives the groups of filter elements from a preceding feed station or creates the groups of filter elements, receives respective filter elements, and inserts the respective filter elements into the groups of filter elements.
The assembly machine also comprises a first wrapping unit, which receives a succession of groups of filter elements from the combining unit, feeds the groups of filter elements perpendicularly to their central axis, and winds a first sheet of wrapping material partly about each group of filter elements. The first wrapping unit feeds the groups of filter elements aligned axially but not contacting end to end, to allow a follow-up station to insert granules and/or similar particles into the gaps between adjacent filter elements.
The assembly machine also comprises a further wrapping unit, which receives a succession of groups of filter elements from the first wrapping unit, feeds the groups of filter elements perpendicularly to their central axis, and winds a second sheet of wrapping material partly about each group of filter elements, so it overlaps the first sheet of wrapping material, to complete the filter, to which a tobacco portion is then connected.